Celestial navigation (quiz) - Page 4 - SailNet Community
Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.

Reply
 
LinkBack Thread Tools
post #31 of 53 Old 02-10-2010
Senior Member
 
Join Date: Jun 2006
Posts: 5,006
Thanks: 5
Thanked 18 Times in 18 Posts
Rep Power: 12
     
Quote:
Originally Posted by AdamLein View Post
WM: you're close...
Well if I am close I'll just go all the way to the South Pole then.

What are you pretending not to know ?

Please support my
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wind_magic is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #32 of 53 Old 02-10-2010 Thread Starter
Senior Member
 
AdamLein's Avatar
 
Join Date: Nov 2007
Location: SF Bay area
Posts: 1,925
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 8
 
Correct

Next:


It is almost noon and the moon is just beginning to rise. What phase is it?

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
AdamLein is online now  
Quote Quick Reply Share with Facebook
post #33 of 53 Old 02-10-2010
Senior Member
 
Join Date: Jun 2006
Posts: 5,006
Thanks: 5
Thanked 18 Times in 18 Posts
Rep Power: 12
     
Quote:
Originally Posted by AdamLein View Post
Correct

Next:


It is almost noon and the moon is just beginning to rise. What phase is it?
Hmm, that would be a waning half moon ?

Yes, it would be a half moon with the light side facing the Sun's direction, I'm wrong, that would be a waxing half moon, after new and before full.

That right ?

What are you pretending not to know ?

Please support my
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wind_magic is offline  
Quote Quick Reply Share with Facebook
post #34 of 53 Old 02-10-2010 Thread Starter
Senior Member
 
AdamLein's Avatar
 
Join Date: Nov 2007
Location: SF Bay area
Posts: 1,925
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 8
 
Well, the light side of the moon is always facing the sun for obvious reasons, but yes, you're right

Technically there's no such thing as a "half moon". The name of the phase is the third quarter.

I like to use the moon to help with navigation in the woods. You can usually deduce whether it's waxing or waning by time of day or night, and then you can roughly determine east and west.

Next quiz question:

I am using an artificial horizon to take sights with a sextant. What dip correction should I apply?

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
AdamLein is online now  
Quote Quick Reply Share with Facebook
post #35 of 53 Old 02-10-2010
Senior Member
 
Join Date: Jun 2006
Posts: 5,006
Thanks: 5
Thanked 18 Times in 18 Posts
Rep Power: 12
     
Quote:
Originally Posted by AdamLein View Post
Well, the light side of the moon is always facing the sun for obvious reasons, but yes, you're right
I was thinking aloud when I wrote that, trying to figure out if it was waxing or waning, I had my head tilted sideways and was thinking about the light being on the right side when I wrote that the light would be on the Sun side.

Quote:
Technically there's no such thing as a "half moon". The name of the phase is the third quarter.
Here there is a half moon, we don't care what scientists call it.

Quote:
Next quiz question:

I am using an artificial horizon to take sights with a sextant. What dip correction should I apply?
I don't know the answer to that one.

What are you pretending not to know ?

Please support my
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wind_magic is offline  
Quote Quick Reply Share with Facebook
post #36 of 53 Old 02-10-2010
Senior Member
 
Join Date: Jun 2006
Posts: 5,006
Thanks: 5
Thanked 18 Times in 18 Posts
Rep Power: 12
     
Quote:
Originally Posted by AdamLein View Post
The name of the phase is the third quarter.
I wonder about this, you said the Moon was rising at noon, right ? That phase seems like it would be called the first quarter, not the third, because it would be the first quarter moon after the new moon, waxing, not the last quarter before the new moon which is waning and setting at noon.

What are you pretending not to know ?

Please support my
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wind_magic is offline  
Quote Quick Reply Share with Facebook
post #37 of 53 Old 02-11-2010 Thread Starter
Senior Member
 
AdamLein's Avatar
 
Join Date: Nov 2007
Location: SF Bay area
Posts: 1,925
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 8
 
Quote:
Originally Posted by wind_magic View Post
I wonder about this, you said the Moon was rising at noon, right ? That phase seems like it would be called the first quarter, not the third, because it would be the first quarter moon after the new moon, waxing, not the last quarter before the new moon which is waning and setting at noon.
Ah, crap, you're right. If the moon is rising at noon, the sublunar point must be east of (CCW from above) the subsolar point, not west as I had in the picture in my head. Thanks

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
AdamLein is online now  
Quote Quick Reply Share with Facebook
post #38 of 53 Old 02-14-2010
Senior Member
 
Join Date: Jun 2006
Posts: 5,006
Thanks: 5
Thanked 18 Times in 18 Posts
Rep Power: 12
     
If you spread your thumb from the rest of your fingers making an "L" shape, and you reach out into the sky with the tip of your thumb covering an object in the sky, approximately how many degrees away will the tip of your index finger be ?

What are you pretending not to know ?

Please support my
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wind_magic is offline  
Quote Quick Reply Share with Facebook
post #39 of 53 Old 02-14-2010 Thread Starter
Senior Member
 
AdamLein's Avatar
 
Join Date: Nov 2007
Location: SF Bay area
Posts: 1,925
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 8
 
13 degrees... but I cheated and used a sextant

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
AdamLein is online now  
Quote Quick Reply Share with Facebook
post #40 of 53 Old 02-14-2010 Thread Starter
Senior Member
 
AdamLein's Avatar
 
Join Date: Nov 2007
Location: SF Bay area
Posts: 1,925
Thanks: 6
Thanked 7 Times in 6 Posts
Rep Power: 8
 
Quote:
Originally Posted by AdamLein View Post
I am using an artificial horizon to take sights with a sextant. What dip correction should I apply?
Dip correction is applied because your eye isn't right on the surface of the Earth; the higher you get, the farther you can see and so the lower the horizon appears, adding a few minutes of arc to your measurements.

An artificial horizon is a reflecting surface parallel to the horizon; you line up the object being sighted with its own reflection, so you're never looking at the horizon, so there is no dip correction.

My next question: suppose late tonight, Feb 14, the bright star Sirius passes directly overhead at 0800 GMT. What is my latitude and longitude?

p.s. this online nautical almanac might help

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
AdamLein is online now  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Basic Celestial Concepts Jim Sexton Seamanship Articles 0 06-28-2004 08:00 PM
Working With the StarsóCelestial Navigation Jim Sexton Seamanship Articles 0 05-06-2003 08:00 PM
Working With the StarsóCelestial Navigation Jim Sexton Her Sailnet Articles 0 05-06-2003 08:00 PM
Navigation Basics Jim Sexton Learning to Sail Articles 0 01-04-2002 07:00 PM
Navigation Basics Jim Sexton Her Sailnet Articles 0 01-04-2002 07:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome